Bill deformities in songbirds

This compilation of bill deformities is property of the Rouge River Bird Observatory. Do not use or cite without written permission. Copyright for photos is held by photographers. Please do not use without permission from individual listed.

Flycatchers to Horned Lark (pg 1)
Swallows through bluebirds (below)
Thrushes through European Starling (pg 3)
Warblers through towhees (pg 4)
Sparrows through orioles (pg 5)
Purple Finch through House Sparrow + Literature Cited (p6)
Bill Tumors, Most Due to Avian Pox

Swallows through bluebirds




Barn Swallow (Hirundo rustica)13 Aug 2008; HY-U; Harrison Twp., Macomb Co., MI; maxilla strongly curvedAllen Chartier (amazilia1 AT comcast DOT net)
Barn Swallow24 March 2009; Holbrook, AZ; maxilla slightly elongated and hooked Eric Hough (erh36 AT nau DOT edu)


Carolina Chickadee (Poecile carolinensis)late Oct 2005; U-U; Crosby, Harris Co., TX; maxilla twice as long as lower, curved downRicci Deibert (riccideibert
Chestnut-backed Chickadee
(Poecile rufescens)
Chestnut-backed Chickadee10 Oct 2006; U-U; Goleta, CA; maxilla shortJim Greaves (LBVIMAN AT
Black-capped Chickadee (Poecile atricapillus)southcentral Alaska; 500+ birds, mostly with very elongated maxillas since 1991Colleen Handel (colleen_handel
AT USGS Alaska Biological Science Center (click here for more info);  Van Hemert 2007
Black-capped ChickadeeKenabeek, OntarioKinch 1998
Black-capped Chickadee11 Oct 2005; HY-U; maxilla was elongated and crossed; Rector, PA
Powdermill Nature Reserve, Robert S. Mulvihill (mulvipnr AT westol DOT com)
Black-capped Chickadee (?)26 Nov 2006; HY-U; maxilla 9mm long and twisted left, mandible 7mm and twisted right, bird also small, possibly Carolina
Chickadee (P. carolinensis) or hybrid; Schuylkill Haven, PA
Scott Weidensaul (scottweidensaul AT
verizon DOT net)
Black-capped Chickadee2007; U-U; maxilla slightly elongated; Whidbey Island, Island Co., WACraig Johnson (highseasmarine AT
Black-capped Chickadee3 Jan 2009; both maxilla and mandible elongated and crossed; South Euclid, OHJim Heflich (laureldocAT sbcglobal
DOT net)
Black-capped Chickadee26 Mar 2011; AHY-U; Fairbanks, AK; maxilla elongated and decurvedFlickr
Black-capped Chickadee30 Dec 2010; U-U; Vermont; maxilla nearly missing, mandible elongated and curved upFlickr
Tufted Titmouse (Baeolophus
1 Feb 1999; SY-U; Rector, PA; maxilla crossed rightPowdermill Nature Reserve, Robert S. Mulvihill (mulvipnr AT westol DOT com)
Tufted Titmouse2 Oct 2015; U-U (probably HY); Waukesha Co., WI; mandible curved up and crossed with maxillavia Wisconsin Birding Facebook page, Ramona Dabey
(Sitta canadensis)
28 Mar 2004; AHY-M; Dearborn, MI; mandible elongated and crossed to right Rouge River Bird Observatory, Julie Craves (jac.rrbo AT gmail DOT com)
Red-breasted Nuthatch17 Jan 2012; AHY-U (F?); northwest Michigan (Traverse City area); both very elongated, but straightFlickr
(Sitta carolinensis)
Winter 2001-02; U-U; Gardener, MA; both elongated, crossedSigrid Warren
(kolibri23 AT
White-breasted Nuthatch8 Mar 2004; AHY-F; Grosse Pointe, MI; mandible greatly elongated and crossing up and to left, maxilla moderately elongated and crossing down and to right Bill Rapai via Rouge River Bird Observatory, Julie Craves (jac.rrbo AT gmail DOT com)
White-breasted Nuthatch25 Apr 2003; Jackson, NH; 'very crossed'Scott Woodman (scotttheguy AT
White-breasted NuthatchLate April to mid-May 2008; AHY-M (?); Mohnton, Berks Co., PA; both maxilla and mandible extremely elongatedDeb Sardone
(ALineAcross AT aol DOT com)
White-breasted Nuthatch1 December 2008; Empire Gulch, Las Cienegas National Conservation Area, near Sonoita, AZ; both maxilla and mandible extremely elongatedJim Lawrence (jlmotmot AT yahoo DOT com)
White-breasted Nuthatch5 Dec 2010; probable male; Butlerville, OH; maxilla elongated and crossed to right, mandible elongated and possibly curving upwardDoug Gilham (cr8zyhorse AT tds DOT net)
White-breasted Nuthatch6 April 2007; AHY-M; New Bern, Craven Co., NC; maxilla and mandible slightly elongated(?, notes from rehabber indicated "had long bill syndrome"); specimen at NC State Museum of
Natural Sciences
Becky Desjardins
White-breasted NuthatchFall 2011 to at least 7 Dec 2011; U-M; Montague, MI; both very elongatedFlickr
White-breasted NuthatchEarly February 2013; AHY-M; Newark, OH; maxilla and mandible extremely elongatedVia Ohio Birds and Biodiversity blog
White-breasted Nuthatch20 Jan 2014; AHY-M; Streator, IL; maxilla elongated and crossed over elongated and blunt mandibleFlickr
(Sitta pusilla)
Photo dated April 2007; both maxilla and mandible grossly elongated, gapped; Atlanta, GAFlickr
Brown-headed Nuthatch6 Dec 2011; U-U; Decatur, DeKalb Co., GA; maxilla elongated and slightly downcurved, forming a gap with the mandibleRebecca Kerimbaev (rebecca DOT kerimbaev AT gmail DOT com)
Brown Creeper (Certhia americana)27 Oct 1996; HY-U; Rector, PA; maxilla and mandible crossedPowdermill Nature Reserve, Robert S. Mulvihill (mulvipnr AT westol DOT com)
Brown Creeper12 Nov 2012; U-U; Marsh Creek State Park, Chester Co., PA; crossedFlickr
Carolina Wren (Thryothorus ludovicianus)3 Dec 2013; AHY-U; North Point State Park Baltimore Co., MD; both maxilla and mandible elongated and decurvedFlickr
Cactus Wren
(Campylorhynchus brunneicapillus)
Mid-February 2009; AHY-U; maxilla and mandible appear crossed at tips; Desert Botanical Garden, Phoenix, AZTina Wynecoop (wynecoop AT hotmail DOT com); This may be the same bird shown in this photograph ; same location, same year.
Cactus Wren1 May 2009; AHY-U; Tucson, AZ; maxilla and mandible very elongated and curved downwardsJoan Gellatly on Flickr
Winter Wren (Troglodytes
29 Sep 2006; HY-U; Tip of mandible broken off, maxilla appeared extra long and downcurved; Metro Beach Metropark, Macomb Co., MIAllen Chartier (amazilia1
Winter Wren18 Oct 2011; HY-U; Dearborn, MI; bill slightly elongated and crossed at tip, maxilla tip spoon-shapedRouge River Bird Observatory, Julie Craves (jac.rrbo AT gmail DOT com)
American Dipper (Cinclus mexicanus)Spring 2004; bird banded as normal juvenile 18 Jul 2003 in Whitewood Creek, SD returned dead with bill slightly crossed at tipDoug Backlund (Doug.Backlund
(Regulus satrapa)
HY-F; 20 Oct 02; Holiday Beach, Essex Co., Ontario, CanadaAllen Chartier (amazilia1 AT
Golden-crowned Kinglet1 Nov 2011; HY-M; maxilla slightly elongated and hooked; Pelee Is. Bird Obs., Pelee Island, Essex Co., ONFlickr
Eastern Bluebird (Sialia sialis)3 Feb 2013; AHY-F; Lodi Twp., Washtenaw Co., MI: bill crossed approx. at mid-way pointRouge River Bird Observatory, Julie Craves (jac.rrbo AT gmail DOT com)
Eastern Bluebird18 Nov 2012; U-M; Red River WLR HQ Unit in Bossier City, LA about 50 yards from the HQ building; crossed at tipFlickr
Eastern Bluebirdphoto dated 28 Nov 2013; U-M; Starkey Wilderness Park, Pasco Co., FL; slightly crossed at tipFlickr
Western Bluebird (Sialia
U.S.Eltzroth 1996
Western Bluebird17 Jun 2014; U-F; Rancho Santa Margarita, Orange County, California; severely twisted, mandible curves upward and left, maxilla veers toward the right.Flickr
Mountain Bluebird
(Sialia currucoides
late March 2008; Sanders Co MT; maxilla slightly elongaged and hookedJim Greaves (LBVIMAN AT BLACKFOOT.NET)

Maxilla = Top, Mandible = Bottom.

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